14 C.F.R. § 389.24
A foreign air carrier, or such carriers, if from the same country, acting jointly, may apply for a waiver of the requirements of this part based on reciprocity for U.S. air carriers contained in the requirement of their home governments, or as provided in a treaty or agreement with the United States. To apply for a waiver under this section, foreign air carriers shall send waiver requests to the Director, Office of International Aviation. The request should include applicable official government rules, decisions, statements of policy, or comparable evidence concerning filing fees for U.S. air carriers, or for all carriers serving that country. Once a waiver has been granted for a specific country, no further waiver applications need be filed for that country.
14 C.F.R. §389.24